Adjustable gin pole



April 3, 1956 c. w. JoHNsToN 2,740,537

ADJUSTABLE GIN POLE Filed May 6, 1955 2 Sheets-Sheet l INVENTOR.

A7702A/5Y5 2 Sheets-Sheet 2 Filed May 6, 1955 INVENTOR. 0/421 E5 M4 Jfl/l/VJfO/V ADJUSTABLE GIN POLE Charles W. Johnston, Shreveport, La.

Application May 6, 1955, Serial No. 506,482

3 Claims. (Cl. 212-8) This invention relates to an adjustable head for booms or gin poles.

In many instances, as for example on trucks equipped with crane, lift, or hoisting apparatus, the boom comprises upwardly converging legs, this arrangement being utilized for the purpose of providing increased strength in the boom, as well as distribution of the supported load over a relatively wide base area.

rdinarily, a boom or gin pole head is mounted upon the convergent upper ends of the boom legs more or less permanently, without possibility of adjustment of the overall length of the boom by interchangeability of the head-supporting legs thereof.

Further, the conventional boom head is so designed as to comprise, most usually, a so-called W hook and snatch block. When boom head components of this type are utilized, approximately 12 to 18 inches is generally lost in a vertical direction, when hoisting or loading objects such as poles, girders, or other structural members. This is due to the fact that the conventional equipment is such that for a distance extending downwardly from the upper ends of the convergent legs, the equipment takes up excessive space, preventing hoisting of the load the full vertical distance between the head and ground surface.

In accordance with the present invention, the boom head is removably mounted upon interchangeable, upwardly convergent boom legs, so that the legs can be selected of a particular length, and the head attached to the convergent ends thereof regardless of the particular angular relationship of the boom legs being used.

A further object of importance is to so design the boom head as to permit the supported load to be hoisted the full vertical distance between the upper ends of the boom legs and the ground surface.

Yet another object is to provide a detachable, adjustable boom head which can be connected to selected supporting legs with maximum ease and speed, and can be detached from said legs with equal facility.

Yet another object of the invention is to so form the boom head that when it is attached to the selected boom legs, it will cooperate with the legs in providing a particularly strong boom assembly capable of use in hoisting heavy loads.

Other objects will appear from the following description, the claims appended thereto, and from the annexed drawing, in which like references characters designate like parts throughout the several views, and wherein:

Figure 1 is a side elevational view of a boom apparatus equipped with a head formed according to the present invention;

Figure 2 is an enlarged side elevational view of the head per se;

Figure 3 is a sectional view on line 3-3 of Figure 2; portions being broken away; and

Figure 4 is a sectional view on line 4-4 of Figure 3.

The reference numeral designates a supporting plat- States Patent form. This can be a stationary platform, or alternatively and more usually, the bed of a truck.

Mounted upon the platform 10 is a prime mover 12, adjacent a winch base 14, on which is mounted a winch 16, powered by the prime mover.

Adjacent the opposite sides of the platform, at the ends thereof remote from the prime mover, there are fixedly mounted boom leg support bases 20, having upstanding ears 22 swivelly mounted upon the respective bases for rotation about vertical axes. Pivot pins 24 extend between the ears 22 of each base 20, and pass through bifurcated leg sockets 26. The sockets are thus mounted upon the bases 20 for swinging movement about a horizontal axis constituted by the pins 24, and further, are rotatable about the vertical axes of the support members 22.

Removably seated at their lower ends in the sockets 26 are upwardly convergent boom legs 23. After insertion in the boom sockets, the legs 28 are secured against withdrawal from the sockets by cross pins or the like extending through the lower ends of the legs and the socket walls.

At this point, it will be understood that any of various other means may be employed to provide for the desired vertical and horizontal swinging movements of the legs. For example, the sockets can be permanently secured to the lower ends of the legs, with the sockets being detachably and pivotally connected to upstanding support members 22 by means of removable pivot pins 24.

At their upper ends, the legs 28 are adapted to support the removable, adjustable boom head 29 constituting the present invention. The boom head includes socket member 31), formed from the open-ended lengths of pipe stock or the like, said socket members at their lower ends being adapted to receive the upper ends of the boom legs in the manner shown in Figure 3, and being welded or otherwise fixedly secured, at their upper ends, to socket member support legs or plates 32. The plates 32, at the ends thereof connected to the socket members, are formed with parallel, transversely spaced, longitudinal slots receiving diametrically opposite portions of the wall of the socket member 30. The socket member, after being extended into said slots, is welded along the edges of the slots to the associated plates 32. As a result, there is defined, within each of the socket members 30, a tongue extending longitudinally thereof, said tongue being the portion of the associated plate 32 disposed between the slots thereof. The tongue provides an abutment, disposed intermediate opposite ends of the socket member, for the upper end of the associated leg 28, as shown in Figure 3.

At their other ends, the plates 32 are welded or otherwise fixedly attached to sleeves 34, said sleeves extending between outwardly projecting ears as welded to the opposite longitudinal edges of reinforcing plates 33 which are in turn welded to the outer surfaces of a pair of sheave plates 46. Pins 42 extend through apertures formed in the respective ears 36 and through the sleeves 34, thus pivotally connecting the plates 32, and hence the socket members 39, to the sheave plates 40, for rotation about parallel axes spaced outwardly from and paralleling the planes of the sheave plates.

In the space between the sheave plates 4%, there is mounted a large diameter sheave or pulley 43, carried by a sheave pin 44 extending through center openings formed in the sheave plates perpendicularly to the axes of swinging movement of the plates 32.

integrally formed upon the sheave plates 40 are extensions 46, having flat, coplanar upper edge surfaces fixedly secured to the underside of a guide plate 48, the end'portions of which extend through longitudinal slots'50 formed in the respective plates 32. By reason of this arrange.

ment, the weight of the supported load is not borne wholly by the hinge pin 42 of the plates 32. Rather, the stress is transmitted, through the boom legs 2% to the plates 32 and pins 42, this being true in any position to which the plates 32 are swung about their respective axes.

Stops or abutments 52 are provided upon the respective end portions of the guide plate 48, limiting swinging movement of the plates 32 in one direction. Said stops in the present instance are comprised of drop pins 52, insertable through apertures formed in the plate 4% Thus, the plates 32 can be swung inwardly toward one another from the positions thereof shown in Figure 3, with the drop pins removed, and thereafter, the drop pins can be reinserted in their associated apertures to provide abutments limiting outward swinging movement of the plates 32. In the illustrated positions of the plates and drop pins, said pins will limit inward swinging movement of the plates 32 toward one another.

Guide line support plates 54 are welded at their inner ends to the outer surfaces of the sheave plates 49, as shown in Figure 2, above the pins 42. The brackets 54 are projected outwardly from the sheave plates 49, above plates 32. and at their outer, free ends, are provided with a sleeve 56 extending transversely between the brackets 54, a pin 58 being passed through the sleeve and through openings formed in plates or brackets 54 in registration with the sleeve to provide, in cooperation with the sleeve, a guide line hitch pin.

From the description which has so far been provided, it will be seen that the overall length of the boom can be selected, by utilizing a pair of boom legs or gin poles 23 of the particular lengths needed for the operation. After the boom legs have been selected, they are attached at their lower ends to the truck bed or support platform in the manner previously described herein, and at their outer ends are engaged in the socket members 30.

It may be noted that in the actual process of connecting the head to the boom legs, ordinarily one socket member would be connected to one of the boom legs and the other socket member to the other leg, after which the legs are swung into whatever angular relationship is necessary to attach them at their lower, divergent ends to the support platform for vertical swinging movement.

A hoisting line 66 is coiled about one drum of the winch, and intermediate its ends is trained about a sheave 62 loosely and pivotally connected to the platform 10 between the bases 26. Thereafter, the line 60 is trained over the sheave 4.2, and at its free end is pro vided with a hook or grapple 64, to which the load is connectable. Rotation of the drum about which line 66 is coiled in a counterclockwise direction in Figure 1 will result in hoisting of the load.

A line 66 is coiled about a second drum of the winch, and has a hook 68 at its free end engageable over the guide line hitch pin 53.

It will be seen that by rotation of the drum about which line 66 is wound in a selected direction, the boom constituted by the legs 28 will be raised or lowered, whichever is desired, and, in any position to which the boom legs are elevated, the line 60 can be separately wound or unwound for the purpose of raising or lowering the load.

Due to the particular formation and relative arrangement of the parts, the load can be hoisted the full vertical distance between the upper ends of the boom legs 2i; and the ground surface, and can, in fact, be hoisted fully up to the peripheries of the sheave plates 40, at the front part of the boom head. This is a substantial increase in 7 said vertical distance as compared to conventional boom heads of the type previously mentioned herein, and adapts the boom apparatus for the handling of loads with considerably more freedom of movement of the portions of the apparatus than has heretofore been the case. This is especially desirable when the loads are elongated, and relatively awkward to handle, this being true, for example, when the objects being lifted are long poles, bars, etc.

It is believed apparent that the invention is not necessarily confined to the specific use or uses thereof described above, since it may be utilized for any purpose to which it may be suited. Nor is the invention to be necessarily limited to the specific construction illustrated and described, since such construction is only intended to be illustrative of the principles, it being considered that the invention comprehends any minor change in construction that may be permitted within the scope of the appended claims.

What is claimed is:

1. A boom head for attachment to a pair of angularly related boom legs, comprising: a pair of sheave plates spaced laterally of one another in parallel planes; a pulley disposed between the plates and mounted thereon for rotation about an axis normal to said planes; a pair of socket members open at one end to receive said legs when aligned coaxially therewith; a pair of socket member support plates atlix'ed to the socket members at the other ends thereof and connected to the sheave plates for swingable adjustment about axes normal to the pulley axis, to align the respective socket members coaxially with their associated legs, and guide means carried by the sheave plates and extending transversely through the support plates for guiding said support plates in their swinging movement.

2. A boom head for attachment to a pair of angularly related boom legs, comprising: a pair of sheave plates spaced laterally of one another in parallel planes; a pulley disposed between the plates and mounted thereon for rotation about an axis normal to said planes; a pair of socket members open atone end to receive said legs when aligned coaxially therewith; a pair of socket member support plates atiixed to the socket members at the other ends thereof, said support plates being pivotally connected to the sheave plates for swingable adjustment about axes normal to the pulley axis, to align the respective support socket members coaxially' with their associated legs, the support plates having longitudinal slots therein;

and means to guide the support plates in their swinging movement, comprising a guide plate supported by the sheave plates and extending transversely of the support plates with its ends loosely engaged in said slots.

3. A boom head for attachment to a pair of angularly related boom legs, comprising: a pair of sheave plates spaced laterally of one another in parallel planes; a pulley disposed between the plates and mounted thereon for rotation about an axis normal to said planes; a pair of socket members open at one end to receive said legs when aligned coaxia'lly' therewith, a pair of socket memher support plates affixed to the socket members at the other ends thereof, said support plates being pivotally connected to the sheave plates for swingable adjustment about axes normal to the pulley axis, to align the respective support socket members coaxially with their associated legs, the support plates having longitudinal slots therein; extensions formed upon the respective sheave plates; and means to guide the support plates in their swinging movement, comprising a guide plate lying in a plane normal to the planes of the sheave plates and supported intermediate its ends upon said extensions, said guide plate being disposed transversely of the respective support plates and having its ends loosely engaged in the slots of the support plates.

References Cited in the file of this patent UNITED STATES PATENTS 2,190,258 Colorigh Feb. 13, 1940 2,436,510 Ferguson Feb. 24, 1948 2,625,275 Ashton Jan. 13, 1953 2,625,371 Dunn Jan. 13, 1953 

